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Topic: looking to replace a 10 dip switch setup with arduino  (Read 100 times) previous topic - next topic

Roughneck

Hi looking for some guidance on a couple of things on a prototype I am trying to build.

 I want to replace a 10 dip switch bar on a device with a arduino controller and be able to set the dip switches and activate the unit via Bluetooth from my phone that would be 10 separate channels in a on or off state at the same time and then a single channel to activate the controller.The device I am doing this to is powered by 9 volt and there is 9 volt going past each dip switch unless in a off state when the activate button is pressed. The goal is the be able to manipulate the dip settings from the phone and activate any combination of on off.


1. what board and extra stuff to buy or possible kit that might suit my needs working on a small budget .

2. is 11 independent switches possible 10 toggled to on or off at the same time and then a single activate for a 2 to 3 second time period

3. Can it be run directly off the arduino board to activate the dip circuit being 9v  or do i need a digital switch of some kind to replace the dip switch from what I have read 5v output is max on arduino.


Any help on what i should buy would be great dont want to buy a bunch of stuff only to find out it was not what i really needed.

Thanks
       




   

OldSteve

What is the device? A bit more info on it's inputs would help.

You can't connect the Arduino directly to the 9V inputs, even if they're CMOS inputs with no pullups. 5V is probably not high enough to register as HIGH.

You could use pullup resistors to 9V on the device inputs, (if they don't already exist), then a pair of 8-channel open-collector arrays like the ULN2803 IC. It uses Darlington transistors for high current applications, but would work fine for your purpose. There's probably a 16-channel chip that's similar too, but you'd need to search. I can't think of one off the top of my head.

You could use a pair of shift registers with open-collector outputs instead too, to save pins, and clock the values into the shift registers. Something like a TPIC6B595. (Again, really intended for higher currents, but they'd work fine.)
Someone else might be able to suggest more suitable ICs.

Edit: You could use 11 independent NPN transistors, too, but a couple of ICs are probably a better idea.
Please do not PM me for help. I am not a personal consultant.
And others will benefit as well if you post your question publicly on the forums.

PaulRB

Are you certain that the circuit runs at 9V? Perhaps the 9V battery is regulated to 5V to run the circuit, which would make life easier for you. Use a multimeter to check the actual voltage on pcb tracks or solder points.

But if this whole circuit ultimately operates a relay or something, it would be easier to replace the whole board with a new circuit that runs at 5V and has an Arduino and a new relay. So tell us more about what the current circuit does, perhaps with pictures or a diagram.

DrDiettrich

You can use discrete transistors or transistor arrays for driving the 9V dip switch inputs, provided their other leg is connected to ground. Otherwise you'll have to use opto couplers, for switches to other signal lines.

dave-in-nj

First, you need to test the switches.  
do they pass 9 volts ?  that would put them on the high side.
do they then go into a voltage divider and pass 5 volts to your circuit ?

if you change one while the unit is running, does the switch do anything? or do you have to have a power re-set ?

reverse hacking requires some careful inspections and testing.  testing for both operation as well as the physical aspects.




liudr

Is the 9V on the device provided by a 9V battery or some AC adapter? DIP switches cost no electricity to operate but arduino will cost some power. If your device runs on a 9V battery, arduino will drain it to the point that it will no longer work after a couple of days.

Here is a post about reducing power consumption if you're using an arduino nano on batteries:

http://forum.arduino.cc/index.php?topic=418299.0
Serial LCD keypad panel,phi_prompt user interface library,SDI-12 USB Adapter

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